Re: [PATCH 3/3] Use g_new() & friends where that makes obvious sense

[Markus Armbruster]

Eric Blake <eblake@redhat.com> writes:

> On Mon, Mar 14, 2022 at 05:01:08PM +0100, Markus Armbruster wrote:
>> g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
>> for two reasons.  One, it catches multiplication overflowing size_t.
>> Two, it returns T * rather than void *, which lets the compiler catch
>> more type errors.
>> 
>> This commit only touches allocations with size arguments of the form
>> sizeof(T).
>> 
>> Patch created mechanically with:
>> 
>>     $ spatch --in-place --sp-file scripts/coccinelle/use-g_new-etc.cocci \
>>           --macro-file scripts/cocci-macro-file.h FILES...
>> 
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> ---
>
> I agree that this is mechanical, but...
>
> <snip>
>>  qga/commands-win32.c                     |  8 ++---
>>  qga/commands.c                           |  2 +-
>>  qom/qom-qmp-cmds.c                       |  2 +-
>>  replay/replay-char.c                     |  4 +--
>>  replay/replay-events.c                   | 10 +++---
>>  scripts/coverity-scan/model.c            |  2 +-
>
> ...are we sure we want to touch this particular file?

Good catch!

>> diff --git a/scripts/coverity-scan/model.c b/scripts/coverity-scan/model.c
>> index 9d4fba53d9..30bea672e1 100644
>> --- a/scripts/coverity-scan/model.c
>> +++ b/scripts/coverity-scan/model.c
>> @@ -356,7 +356,7 @@ int g_poll (GPollFD *fds, unsigned nfds, int timeout)
>>  typedef struct _GIOChannel GIOChannel;
>>  GIOChannel *g_io_channel_unix_new(int fd)
>>  {
>> -    GIOChannel *c = g_malloc0(sizeof(GIOChannel));
>> +    GIOChannel *c = g_new0(GIOChannel, 1);
>>      __coverity_escape__(fd);
>>      return c;
>>  }
>
> Our model has a definition of g_malloc0(), but I'm not sure whether
> Coverity picks up the macro g_new0() in the same manner.

I believe it does, by parsing the macro definition from the header.

Regardless, I'd prefer to keep model.c self-contained.  I'll drop this
hunk.

Thanks!